I would suggest a main current that uses the length of the tank, but then gets pushed up or down at the far end. By placing pieces of
live rock in the current , you can create little eddies, or twists in the water , which should leave some calmer hiding places for those who don't want to swim constantly. My Tank is 48" long 18" deep and 30" tall. I use the water return nozzles as a star and then have four large powerheads to circulate the whole tank. Two of the powerheads shut off with the main lights to simulate calm in the evening.
check out my album, there are some shots that might show what I did, it seems to work really well.
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